Azo dyestuffs



Patented Feb. 1, 1938 UNITED STATES PATENT OFFICE AZO DYESTUFFS No Drawing. Application March 30, 1936, Serial No. 71,797. In Germany April 4, 1935 stuffs, more particularly it relates to dyestuffs which may be represented by the general formula:

In the said general formula X is a member of the group consisting of hydrogen and N=NR5, and R stands for a radical of the benzene series or of the l,1-diphenyl series bearing the azo groups in the 4,4-positions, such as the benzene nucleus, which may be substituted, for example by alkyl, halogen, the sulfonic acid group and the carboXylic acid group, or a diphenyl which may bear substituents, such as alkyl, alkoxy, halogen, 20 the nitro group, the sulfonic acid group and the carboxylic acid group, R1 stands for the radical of a naphthol sulfonic acid, capable of coupling twice, such as for aminonapththol sulfonic acids or dihydroxynaphthalene sulfonic acids, R2, R4 and R5 stand for aromatic radicals which may bear substituents, such as alkyl, alkoxy, the nitro group, halogen, the sulfonic acid group and the carboxylic acid group, and which may contain an azo group, R3 stands for a radical of a 1,3-dihydroxy compound of the benzene series.

Those of the above identified dyestuffs, in which R stands for a radical of the benzene series, are obtainable by combining in either order one molecular proportion of a naphthol sulfonic acid r capable of coupling twice, with one molecular proportion of a diazo compound of the benzene series containing a group which is convertible into an amino group, such as for instance a nitro group, and with one molecular proportion of any diazo compound, one of these couplings being effected in an acid, the other coupling in an alkaline medium, then converting into the amino group the group above specified, subsequently diazotizing, coupling in an alkaline medium with one molecular proportion of a 1,3-dihydroxybenzene compound and then with one molecular proportion of a monodiazo compound or either at the same time or successively with two molecular proportions of the same or different monodiazo compound.

Those of my new compounds of the above formula, in which R stands for a diphenyl radical, are obtainable by combining in either order one molecular proportion of a naphthol sulfonic acid capable of coupling twice, with one molecular proportion of a tetrazotized 4,4-diaminodiphenyl compound and onemolecular proportion of any diazo compound, whereby the first coupling is performed in an acid medium, the second in an alkaline medium, then combining with one molecular proportion of a 1,3-dihydroxy compound of the benzene series and coupling the polyazo dyestuff formed with one molecular proportion of a monodiazo compound, or either at the same time or successively with two molecular proportions of the same or of difierent monodiazo compounds.

The dyestufis thus obtained are especially adapted for dyeing leather, yielding in general brown to blackish brown shades and they are particularly distinguished by their good fastness to acids and alkalies, and by their giving full and subdued shades.

The invention is illustrated by the following examples without being restricted thereto:

Example 1.184 kgs. of benzidine are tetrazotized in the known manner and combined, in an acid medium, with 363 kgs. of the sodium salt of 1,8 aminonaphthol-3,6-disulfonic acid. When the formation of the monoazo dyestufi is complete, 209 kgs. of p-sulianilic acid (dihydrate) are diazotized and added, and coupling is effected in a medium alkaline with sodium carbonate.

After the coupling is complete, a solution of 110 kgs. of resorcinol is added to the dyestuff formed. After this, to the coupling mixture a diazo solution prepared from 138 kgs. of p-nitraniline'is added, when the reaction of the diazo compound disappears after about minutes. After the addition of a further solution of 375 kgs. of sodium carbonate in about 1400 litres of water, finally another diazo solution prepared from 138 kgs. of p-nitraniline is added. This final coupling is complete after stirring overnight. The next morning neutralization is effected and the whole rendered weakly acid to acetic acid, and the dye stufi is salted out with 10% of sodium chloride, the percentage being calculated on the coupling volume, and then the dyestufi is pressed.

The dyestuff corresponds to the following formula:

It forms, when dried, a greyish black powder, which dissolves in water with a deep brown coloration in concentrated sulfuric acid with a greyish blue coloration.

Example 2.-In accordance with the indications of Example 1, 184 kgs. of benzidineare tetrazotized and first, in an acid medium, combined with 363 kgs. of the sodium salt of 1.8-aminonaphthol-3,6-disulfonic acid, and then to the dyestuff formed a diazo solution prepared from 218 NH: OH 80311 SOZH - is soluble in water with a clearer brown coloration than that obtained with the dyestufi of Example 1, but otherwise it has the same dyeing properties.

Of course, the diazo compounds of the pnitraniline and the 4-nitraniline-2-sulfonic acid mentioned in Examples 1 and 2 may be substituted by other diazotizing components, such as aniline disulfonic acids, naphthionic acid, naphthylamine disulfonic acids, chloram'line sulfonic acids, anisidine sulfonic acids, aminoazobenzene monoor disulfonic acids and so on.

Example 3.To the trisazo dyestufl obtained according to the directions of Example 1, formed a by combining, in an acid medium, 363 kgs. of the sodium salt of 1,8-aminonaphthol3,6-disulfonic acid with 1 mol. of tetrazotized benzidine and, in an alkaline medium, with the diazo compound prepared from 209 kgs. of p-sulfanilic acid (dihydrate), and by coupling with kgs. of resorcinol, after this latter, coupling is complete, a diazo solution prepared from 209 kgs. of p-sulfanilic acid (dihydrate) is added. This coupling is quickly complete. Then 375 kgs. of sodium carbonate dissolved in waterare added to the coupling mixture and the final coupling is effected, after the addition of the diazo compound prepared from 138 kgs. of p-nitraniline, by stirring over night. The next morning the dyestuff is worked up according to the method described in Example 1. It corresponds to the following formula:

noas SOxH N=N-Q03 nents, which may be used for the final coupling with the trisazo dyestufi formed from 'benzidine, the sodium salt of 1,8-aminonaphthol-3,6-disulfonic acid, p-sulfanilic acid and resorcinol. The final components applied in Example 3, i. e. the

p-sulfam'lic acid and the p-nitraniline, may be substituted by others, as for instance by p-nitraniline disulfonic acids, and by anilines or aniline sulfonic groups substituted by chlorine, hydroxyl or alkoxy groups, by picramic acid,'1,3-diaminol-nitrobenzene and so on. importance, however, what is the order of applying these two components for final diazotization.

Thus not only the selection of the diazotizing 'It seems to be of components but also the order in which they are,

one after another, allowed to act upon the trisazo dyestuff formed, gives a far-reaching possibility of varying the properties of the dyestuffs.

Example 4.184 kgs. of benzidine are tetrazotized and combined, in an acid medium, with 285 kgs. of the sodium salt of 2-amino-5-naphthol- 7-sulfonic acid. When the formation of the monoazo-dyestuff is complete 209 kgs. of psulfanilic acid (dihydrate) are diazotized and added, and coupling is effected in a medium alkaline with sodium carbonate After coupling is complete a solution of 110 kgs. of resorcinol is added to the dyestuff formed. When this step of the formation of the dyestuff is complete, to the coupling mixture a diazo solution prepared from 218 kgs. of 4-m'traniline-2-sulfonic acid is added, which latter disappears after a short duration of coupling. After a further solution of 3'75 kgs. of sodium carbonate in about 1400 litres of water is added, finally a diazo solution prepared from 138 kgs. of p-nitraniline is added. This coupling is complete over night. The next morning the dyestuff is salted out with 5% of sodium chloride while neutralizing at the same time until the reaction is only weakly alkaline, and then squeezed.

The dried dyestuff, corresponding to the following formula:

OH Hols N=NOSOsH N=N N02 I1I=N OH a lag.

dissolves in water with a deep brown, in concentrated sulfuric acid with a blackish blue coloration.

It is obvious that far-reaching variations can be made in the shade of the dyestuffs manufactured in accordance With this process, by substituting the diazo compounds coupled to the fundamental structure of .the dyestuff benzidineazo-2-arnino-5-naphthol-7-sulfonic acid azoresorcinol by suitable monodiazo or diazoazo compounds other than indicated in the example, as for instance by p-aminobenzoic acid, l-hydroxy-4-aminobenzene-Z-carboxylic acid, aniline sulfonic acids containing chlorine or hydroxyl or alkoxy groups, picramic acid, 1,3-diamino-4-nitrobenzene or aminoazobenzene-monoor disul ionic acids. In this example also not only the selection of the diazotization components but the succession of their coupling presents a far-reaching possibility of varying the dyestuff properties.

Example 5.285 kgs. of the sodium salt of 2- amino-S-naphthol-l-sulfonic acid are combined, in an acid medium, with the diazo compound prepared from 209 kgs. of p-sulfanilic acid (dihydrate). When the formation of the monoazo dyestuff is complete a tetrazo solution prepared from 184 kgs. of benzidine is added and the reaction mixture is rendered alkaline with sodium carbonate. When the coupling, is complete a solution of 110 kgs. of resorcinol is added and coupling is effected in a medium alkaline with sodium carbonate.

To the coupling mixture formed in this manner a diazo solution prepared from 218 kgs. of 4-nitraniline-2-sulfonic acid is added, which'disappears after a short duration of coupling. After a further solution of 3'75 kgs. of sodium carbonate in about 1400 litres of Water is added, finally a diazo solution prepared from 138 kgs. of p-nitraniline is added. This coupling is complete over night. The next morning the dyestuff is salted out with 5% of sodium chloride, while neutralizing at the same time until the reaction is only weakly alkaline, and then squeezed and dried. It corresponds to the following formula:

N= -QOH r H N=NAONO:

Example 6.138 kgs. of p-nitraniline are diazotized in the known manner and combined, in an acid medium, with 285 kgs. of the sodium salt of 2-amino-5-naphthol-7-sulfonio acid. When the formation of the monoazo dyestufi is complete, there is added the diazo compound prepared from 209 kgs. of p-sulfanilic acid (dihydrate), and coupling is effected in a medium alkaline with sodium carbonate. After coupling is complete, a solution of about 420 kgs. of sodium sulfide is addedto the coupling mixture, and the whole is stirred until the reduction of the nitro group is complete. Thereupon, for removing the sulfur, the dyestuff solution is rendered acid to Congo red, and the dyestuff which has been precipitated and squeezed oil is dissolved in an aqueous solution of sodium carbonate and the solution filtered. To this solution a solution of about '70 kgs. of sodium nitrite is then added, the solution thus obtained is rendered acid to Congo red with hydrochloric acid, at a low temperature, and stirred until diazotization is complete. Thereupon a solution of 110 kgs. of resorcinol is poured into the diazotization mixture, and coupling is effectedin a medium alkaline with sodium carbonate. When coupling is complete, there is poured into the coupling mixture a diazo solution prepared from 218 kgs. of 4- nitraniline-Z-sulfonic acid, which disappears after a short duration of coupling. After the addition of a solution of about 350 kgs. of sodium carbonate in 1400 litres of water, finally the diazo solution prepared from 138 kgs. of p-nitrani- OH- noz s N=NOSO1H N It dissolves in water with a dark brown and in concentrated sulfuric acid with a black coloration and, on leather, it yields productive, full and subdued shades.

Example 7.138 kgs. of p-nitraniline are diazotized in the known manner and coupled, in an acid medium, with 363 kgs. of the sodium salt of l,8-aminonaphtho1-3,6-disulfonic acid. When the coupling of this monoazo dyestufi is complete, 209 kgs. of p-sulfanilic acid are diazotized and the product added, and coupling is effected in a medium alkaline with sodium carbonate. After this coupling is complete, a solution of about 420 kgs. of sodium sulfide is added to the dyestuff, and the Whole is stirred until the reduction is complete. This reduction mixture is rendered acid to Congo red with hydrochloric acid, and the dyestufi thereby separated is squeezed ofi and, for removing the sulfur, dissolved in a hot aqueous solution of sodium carbonate and filtered. After cooling, there is added to the filtrate a solution of '70 kgs. of sodium nitrite, the mixture is rendered acid to Congo red at a low temperature, and stirred until diazotization is complete. 'I'hereupon a solution of kgs. of resorcinol is poured into the diazotization mixture, and coupling is effected in a medium alkaline with sodium carbonate. When coupling'is complete, to the coupling mixture a diazo solution prepared from 218 kgs. of 4-nitraniline-2-sulfonic acid is added, which latter component disappears after a short time. After a solution of about 350 kgs. of sodium carbonate in 1400 litres of Water has been added, there is finally added a diazo solution prepared from 138 kgs. of p-nitraniline. Coupling is complete over night. The next day the dyestuff is salted out with about 10% of sodium chloride while at the same time adding sodium carbonate until there is a weakly alkaline reaction, and then squeezed.

The dyestufi corresponds to the following formula: V

HzN on III==N N=NGS 03H N=N N01 fi N- OH S 0:11

H-acid H anilin 7 coupling acid Res. p-sulfauilic acid i. alkaline coupling 7' couphng acid Res. 7

p-sulfamhc acid p-sulfanilic acid 1 alkaline coupling (3) H-acid aniline p-sulfanilic acid a Res.

p-nitraniline alkaline coupling (4) H-acid 7' coupling/ 7 acid Res.

p-nitraniline p-sulfanilic acid l/ p-nitraniline Cal 7' coupling acid p-sulfanilic acid 1 Res.

p-sulfanilic acid alkaline coupling (7) H-acid p-nitraniline coupling/ acid \ p-nitranline |Z Res.

p-m'traniline (8) alkaline coupling )H-acide-H:N NO: coupling NH: acid p-sulfanilic acid Res.

p-nitmniline alk. coupling (9) l-ammo-8-hydroxy- 4 -sulfonic acid ifig coup? acid p-nitraniline-o-sulionic acid acid p sulianilic acid N l/ Res.

p-sulfamhc acid (12) alkaline coupling H-acid aniline coupling acid \ SOaH Res. -H:N NO:

(13) alkaline coupling H-acid -aniline coupling 7| SQzH acid B\ /H1N NO:

Res.

HaN NO:

alkaline coupling (14) 7 H-acid+-aniiine coupling/ acid 'Rp-nitraniline alkaline coupling (15) H-acid coupling acid ResA-y-acid alkaline coupling (16) 7 IEI-acid ---aniline couplin acid \ -y-acid I! Res.R

p-nitraniline l alkaline coupling 7) H-acid --aniline coupling acid Res o-chloro-aniline p sulfonic acid alkaline coupling (18) V 7 H-acid -aniline coup? acid p-nitraniline Res.

Ro-chloro-aniline p-sulfonic acid alkaline coupling (19) H-acid(-aniline coupling acid \ 2, 5-dichloroaniline-siflfonic acid \I i! Res.

alkaline coupling (20) H-acid aniline coupling/ acid \ 2, S-dichloroanilinesulfonic acid Res.

p-nitraniline alkaline coupling (21) H-acid(-aniline coupling acid s 03H /HIN NO:

Res. scan alkaline coupling (22) H-acid(-anili.nc

coupling acid \ HzN N O:

\i i! l Res. NH:

p-mtranillne alkaline coupling V (23) H-acid '-m-sulfanilic acid 7 coupliy acid -nitran1line Resk a p-nitranlline alkaline coupling 7 (24) H-acid ---aminoazobenzenmonosulfonic acid coupling l acid \ p-nitran iline Res.

p-nitraniline alkaline coupling I (25) H-acid('-aminoazobcnzcne- 7' disulfonic acid coupling acid \ p-nitraniline \i i! Res.

p-mtranlline alkaline coupling (26) H-acid p-sulfanilic acid coupling acid 7 B\ p-nitraniline L/ Res.

p-sulfanilic acid (27) V alkaline coupling I V )H-acid p-sulfanilic acid coup? acid p-nitraniline 1! Res.

m-nittaniline (28) alkaline coupling H-acid -p-sulfanilic acid coupling/ I ac? bm-niggo- 03H enzi inc Res p-nitraniline (29) V alkaline coupling H-acid --p-sulfanilic acid coupling acid benzidine-m- S 03H disulfonicacid\ I Res p-nltranillne (30) alkaline coupling J-acid(----p-sulianilic acid coupling acld m-nitro- S 03H benzidine /H:N NOa' Res.

p-mlzranilincv alkaline coupling -J-acid ---+p-sulfanillc acid coupling acid benzidlne-m- SOBH disulionicacld\ l \l i! Res.

p-nltraniline s2 alkaline coupling J-acid aniline coupling/ acid H2-)Res.

p-nitraniline (33) alkaline coupling J-acid(---naphthi0n.ic acid coupling/ acid SOzH

H N N01 NEH Res.

p-nitranilinc (34) alkaline coupling J-acid -1-naphthylamine- 7 3, G-disulfonic acid coupling acid SOaH

HaN NO:

NHH Res.

p-nitraniline (35) alkaline coupling J-acid(--p-sulfanilic acid coupling acid N- a SI 0 3H NHz-e Res. 7

p-nitraniline (36) alkaline coupling .T-acide-1-naphthy1amine- 4-sulionic acid coupling acid N H; SIO H 1! NHH Res.

' p-nitraniline (37) alkaline coupling J-acide--1-naphthylamine- T 3, 6-disulf0nic acid coupling acid NH, SOaH HflN N02 NHH Res p-nitraniline alkaline coupling (38) H-acid --p-su1fanilic acid coupling acid 0 H NHZ NONW Res. R

p-m'traniline alkaline coupling (39) flH-acid ---p-sulfanilic acid coup? acid N'Hz NHa\ HaN N02 \I ll 7 m-mtraniline phenyl-alkaline coupling (40) J -acid(--p-sulfauilic acid 7' coupling/ acid NHz'

/HN NO, NH=-- Res.

p-nitraniline phenyl-alkaline coupling (41) .T-acid --p-sulfanilic acid 7| couply acid NHa 03H -NH2 HENONOI I! v Ros. R v

p-nitraniline f fg q r a 81k wherein X is a member of the group consisting (42) gene -S A CidJ p-sulfam'fic acid of hydrogen and N=NR5, and R1 stands for a 1m a radical of an aminonaphthol sulfonic acid capacoup g ble of coupling twice, R2, R4 and R5 stand for 5 acid aromatic radicals yielding on leather in general NH, brown to blackish brown shades of good fast- 1 ness properties.

SOaH '4. Azodyestuffs of the general formula: I t HzN-ONO: 10;

N=NR1N=NR1 NHz Res.\

V p-nitrsniline I claim: 15 1. Azodyestuffs of the general formula:

N=NR1N=NRz V l N=N'-R4 N=N"R4 I I=N OH V H x V wherein X is a member of the group consisting V 25;

of hydrogen and N=N--R5, and R stands for a radical selected from the group consisting of the benzene series and the 1,1'-diphenyl series, bearing the azo groups in the 4,4-positions, R1 stands so for a radical of a naphtholsulfonic acid capable wherein X is a member of the group consisting of hydrogen and N=N-R5, and R1 stands fora radical of Z-amino-5-naphthol-'7-sulfonic acid,

ing on leather in general brown togblackish wmof couplingwtwice, R eRnand R5. stand ior iaro- V W n A brown shades of good fastness properties.

5. The dyestufi having in the free state the following formula:

matic radicals, Rg stands for a radical of a 1,3- .dihydroxy compound of the benzene series, yielding on leather in general brown to blackish brown R2, R4 and R5 stand for aromatic radicals yieldshades of good fastness. properties. 1 7 5 35;

2. Azodyestufi's of the general formula: A 2

N=NR1-N=N--Rz r -N=N 4o OH 40 Hogs N=N-O-s0m sonar 'v wherein X is a member of the group consisting of hydrogen and N=N-R5, and R1 stands for a radical of a naphtholsulfom'c acid capable of 1 h coupling twice, R2, R4 and R5 stand for aromatic yl f g fg g ggg gg gg g figgi radicals yielding on'leather in general brown to blackish brown shades of good fastness properties.

3. A zodyestuifs of the general formula: N=N R -N=NRz 60 N=N-R1-N=N-R,

V IIT=N-'R4 MNQ 65,

V H x V wherein X is a member of the group consisting of hydrogen and N=NR5, and R1 stands for a N: OH radical of a naphtholsulfonic acid coupling twice, R2, R4 and R5 stand for aromatic radicals, H X yielding on leather in general brown to blackish V r 7 brown shades. m

'7. Azodyestuffs of the general formula:

N=NR1N=NR2 (IJHIII wherein X is a member of the group consisting of hydrogen and N=NR5, and R1 stands for a radical of an aminonaphthol sulfonic acid coupling twice, R2, R4 and R5 stand for aromatic radicals, yielding on leather in general brown to blackish brown shades.

8. Azodyestuffs of the general formula:

wherein X is a member of the group consisting of hydrogen and N=N-R5, and R1 stands for a radical of a Z-amino-5-naphthol-7-sulfonic acid,

R2, R4 and R5 stand for aromatic radicals, yielding on leather in general brown to blackish brown shades.

9. The dyestuff having in the free state the following formula:

I 1 1- Hogs N=N- s 0311 N FRIEDRICH SCI-IUBERT. 

